Surgical masks and N95 respirators are examples of personal protective equipment (PPE) which are used to protect the wearer from liquid contamination and airborne particles from contaminating the face. It is important to know the optimal way to prevent airborne transmission. Each type of mask and also cloth face masks serve different functions.
N95 respirators are tested and approved by the NIOSH (National Institute for Occupational Safety and Health). Their intended use and purpose is to protect the wearer from exposure to particles including small particle aerosols and large droplets. They are designed to achieve a very close facial fit and very efficient filtration of airborne particles.
The N95 designation means that when subjected to careful testing, the respirator blocks a minimum of 95% of very small (0.3 micron) test particles. When fitted properly, the filtration capabilities of these type respirators exceed those of face masks. However, they do not completely eliminate the risk of illness. Leakage can occur around the edge of the mask when user inhales. N95 respirators are disposable and ideally should be discarded after each patient encounter and/or when the unit no longer forms an effective seal to the face, becomes wet or visibly dirty, breathing becomes difficult, or it becomes contaminated with blood, respiratory or nasal secretions or other bodily fluids from patients.
N95 masks are typically used in healthcare settings. The CDC does not recommend the general public wear N95 respirators to protect themselves from respiratory diseases including COVID-19. These masks are critical supplies that are primarily reserved for health care workers and first responders as recommended by the CDC.
Surgical masks are loose fitting, disposable devices that create a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. They are typically used to to protect the wearer from splashed sprays and large particle droplets. They also prevent the spread of potentially infectious respiratory secretions from the wearers to others. They are tested and approved by the FDA.
Surgical masks are loose fitting and can vary in design. However, the mask itself is often flat and rectangular in shape with pleats or folds. The top of the mask contains a metal strip which can be formed to a person’s nose. Elastic bands or long straight ties help hold a surgical mask in place while being worn – either looped behind the ears or tied behind the head.
While a surgical mask is meant to block large particle droplets, splashes, sprays or splatter that might contain germs (bacteria and viruses), they do not filter or block very small particles in the air that could be transmitted by sneezes, coughs or certain medical procedures. They do not provide complete protection from germs and other contaminants due to their loose fit between the surface of the face mask and face. They are intended for one use only and should be discarded after each patient encounter.
Cloth face coverings many of which can be homemade, only offer a small degree of protection, but the may also help the slow spread of the COVID-19 virus. These type masks are what the CDC is recommending for use by the general public when in public settings.
Face cloths should not be placed on children under the age of 2, people who have breathing difficulties, people who are unconscious, or people who are unable to remove the mask on their own. They should be washed after each use. When removing a person should be careful not to touch their nose, eyes or mouth and hands should be washed immediately after removal.
They can be made from common materials. It should be kept in mind by wearers of these type masks that they can provide a false sense of security. While they do offer some degree of protection, they offer a lot less protection than respirators or surgical masks. One study indicated that homemade face masks may be half as effective as surgical masks and up to 50 times less effective than N95 respirators. However, they are better than not using any mask and offer some protection especially where social distancing is hard to maintain.